The study looked at how the amount of sand on a beach affects the size of sand dunes in the Netherlands. By using a computer model, the researchers found that the movement of sand along the shore plays a big role in shaping the dunes. When the beach is gaining sand, the dunes grow naturally. But in areas where the beach is losing sand, the dunes need help from human-made additions of sand. Activities like building on the beach and removing plants from the dunes can slow down dune growth. The model used in the study did a good job of predicting how the dunes changed over time. This research helps us understand how dunes evolve over decades, which is important for planning how to protect against flooding and design nature-based solutions.